Try looking at this Custom Number Picker. I would start with that and simply modify the layout of the control to be horizontally oriented.
Another option is to find the source code for the Android 2.3.4 NumberPicker and NumberPickerButton and copy that. This will also require copying the resources required for those controls. Again, you would then need to modify the button layout to be horizontally oriented.
I would not recommend using the NumberPicker from API 11 or greater. You will find that there are numerous depenencies on newer classes that are not available to you with API 8.
